Sometimes we have to accept that we’re a bit out of the ordinary 
But even if not, checking your backup results will remain the same. It’s only when you want to setup or modify a backup, when this would become relevant on mobile.
As the author of the duplicati manual, even that is something of an understatement 
So when it comes to representing users who just want to set up some backups in as little time as possible, I am the authority here 
and I say: this would be a huge improvement:
BTW, as I look at it: the suggested texts are not really that much wider than what they are now. If width is really an issue (have you tried it?), here is a shorter version:
“Keep this number of backups” -> “Backup retention”
“unlimited” -> “unlimited (keep all for ever)”
“until they are older that” -> “keep until backups are older than” (or: “delete when older than”)
“a specific number” -> “Keep this number of backups”